How to Flatten a Wrinkled Paper Collage Without Wetting the Whole Surface

Check the collage in good light before moving it. Look for raised or lifting edges, cracked or powdery media, glossy or tacky adhesive, fragile paper, and objects that stick up from the surface. A collage with attached photographs, pastel, charcoal, thick paint, foil, dried flowers, or layered dimensional pieces needs special caution: pressure may rub, transfer, flatten, or detach those elements. The Canadian Conservation Institute advises leaving cleaning and repairs to a paper conservator because inexperienced treatment can damage works on paper. Its guidance also notes that pastel, chalk, and charcoal can be disturbed by rubbing and even by some plastic sleeves. (Canadian Conservation Institute, “Basic care – Works of art on paper”)

If the collage is valuable, irreplaceable, brittle, moldy, already torn, or has loose or water-sensitive layers, stop at safe storage and ask a paper conservator for advice. Do not use the dry-press method below on a piece that cannot lie flat without force. The aim is to reduce gentle waviness in a stable, flat collage, not to flatten every construction or erase intentional texture.

Use a flat table, two clean, smooth, dry sheets larger than the collage, a stiff flat board, and a modest weight such as a few books. Place the collage on one protective sheet, image side up. Cover it with the second sheet, then set the board on top before adding weight. Keep the board large enough to spread pressure across the full piece, and make sure it does not bow or rock.

The protective sheets are a buffer against surface abrasion and accidental transfer; they do not make every medium safe under pressure. Avoid textured towels, newspaper, tissue that sheds fibers, and plastic film that may cling or trap moisture. Do not put a book directly on the artwork. If anything catches, sticks, or leaves a mark as you position the layers, lift the covering straight up and stop rather than sliding it across the collage.

Start with light, even weight for several hours. Then lift the board and top sheet vertically and inspect the collage without rubbing it. If the waviness is visibly reduced and all elements remain secure, you can continue under the same light pressure for longer, checking periodically. Dry, flat pressing is a low-intervention trial, not a guaranteed repair: the paper may spring back, and a crease or unevenly glued layer may remain.

Use the result to decide whether to stop. A slight improvement with no surface change is a reasonable outcome for a casual journal page. If the wrinkle persists, deepens, or seems to pull surrounding pieces, do not add a heavier stack or keep repeating the process. More weight can compress raised details or stress layers that expand and contract differently.

When one area lifts or buckles, the temptation is to dampen just that spot. Resist it. Paper absorbs moisture, and high humidity can make paper swell and appear wavy or wrinkled; liquid can also affect pigments, inks, and adhesives. A small wet patch is not reliably confined to the visible wrinkle. The Canadian Conservation Institute’s paper-care guidance describes paper’s sensitivity to moisture and recommends that repairs be handled by a conservator.

For a stable collage, keep pressure broad and even rather than pressing only on the wrinkle with a fingertip or a small object. That avoids creating a new dent or concentrating force on a seam. If the raised area is caused by a loose piece, pressing it down may not restore its bond; do not add household glue or tape. The National Archives warns that adhesive tape can stain or embrittle paper over time and that adhesives can cause inks to bleed. (National Archives, “Paper-Based Records”)

An iron, hair dryer, kettle steam, or a damp cloth introduces heat or moisture that is hard to control across a mixed-media surface. These methods can alter the sheen or shape of papers and affect media or adhesive. A National Park Service conservation leaflet describes humidification as a carefully controlled process for paper documents and warns that wetting paper may cause irreversible damage; it then uses blotters and weight for drying. That is specialist guidance, not a recommendation to build a humidification setup for a casual collage at home. (National Park Service, “How to Flatten Folded or Rolled Paper Documents”)

Likewise, do not back-fold the collage to counteract a curl. The National Archives advises against back-folding paper to flatten it and recommends leaving stiff, brittle, damaged, or resistant records alone for conservator-supervised treatment. (National Archives, “Paper-Based Records”)

Once you finish, store the collage flat in a clean folder or shallow box with enough room that corners do not bend. Keep it away from damp, fluctuating environments such as basements and attics; the Canadian Conservation Institute notes that moisture changes can contribute to waviness and damage. If you display the collage, choose a stable location away from direct sunlight and heat, which can fade colors and speed paper deterioration. If it remains visibly wrinkled, preserving its current state is usually preferable to escalating into an uncertain wet treatment.

For a journal or memory collage, the practical test is simple: did light, even dry pressure reduce the waviness without changing the surface or loosening anything? If yes, stop there and store it flat. If not, accept the remaining wrinkle or consult a paper conservator before trying a treatment involving moisture, heat, or adhesive.

• “Basic care – Works of art on paper,” Canadian Conservation Institute
• “Paper-Based Records,” National Archives
• “How to Flatten Folded or Rolled Paper Documents,” National Park Service, Conserve O Gram 13/2